/*
 * Copyright 2002-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using Spring.Expressions;

namespace Spring.Validation;

/// <summary>
/// <see cref="IValidator"/> implementation that supports grouping of validators.
/// </summary>
/// <remarks>
/// <p>
/// This validator will be valid when <b>one and only one</b> of the validators in the <c>Validators</c> collection are valid
/// </p>
/// <p>
/// <c>ValidationErrors</c> property will return a union of all validation error messages
/// for the contained validators, but only if this validator is not valid (meaning, when none
/// of the contained validators are valid).
/// </p>
/// <p>
/// By default, this validator group uses <c><see cref="BaseValidatorGroup.FastValidate"/> == true</c> semantics.
/// </p>
/// </remarks>
/// <author>Aleksandar Seovic</author>
/// <author>Erich Eichinger</author>
public class ExclusiveValidatorGroup : BaseValidatorGroup
{
    /// <summary>
    /// Initializes a new instance of the <see cref="ExclusiveValidatorGroup"/> class.
    /// </summary>
    public ExclusiveValidatorGroup()
    {
        this.FastValidate = true;
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="ExclusiveValidatorGroup"/> class.
    /// </summary>
    /// <param name="when">The expression that determines if this validator should be evaluated.</param>
    public ExclusiveValidatorGroup(string when)
        : base(when)
    {
        this.FastValidate = true;
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="ExclusiveValidatorGroup"/> class.
    /// </summary>
    /// <param name="when">The expression that determines if this validator should be evaluated.</param>
    public ExclusiveValidatorGroup(IExpression when)
        : base(when)
    {
        this.FastValidate = true;
    }

    /// <summary>
    /// Actual implementation how to validate the specified object.
    /// </summary>
    /// <param name="contextParams">Additional context parameters.</param>
    /// <param name="errors"><see cref="ValidationErrors"/> instance to add error messages to.</param>
    /// <param name="validationContext">The object to validate.</param>
    /// <returns><c>True</c> if validation was successful, <c>False</c> otherwise.</returns>
    protected override bool ValidateGroup(IDictionary<string, object> contextParams, IValidationErrors errors, object validationContext)
    {
        ValidationErrors tmpErrors = new ValidationErrors();
        bool valid = false;
        foreach (IValidator validator in Validators)
        {
            bool tmpValid = validator.Validate(validationContext, contextParams, tmpErrors);
            if (valid && tmpValid)
            {
                valid = false;
                if (this.FastValidate)
                {
                    break;
                }
            }
            else if (tmpValid)
            {
                valid = true;
            }
        }

        if (!valid)
        {
            errors.MergeErrors(tmpErrors);
        }

        return valid;
    }
}
